High-quality Mugen creators have done an impressive job reverse-engineering the UMK3 engine.
: Adjustable difficulty (up to 100%), "Watch Mode" for CPU battles, and move lists accessible via the Start button. Ultimate Mortal Kombat 3 Mugen Download
Since there is no single "Ultimate Mortal Kombat 3 Mugen" (there are hundreds of versions made by different creators), the "solid review" usually applies to the most famous "Full Game" compilations or the high-quality characters that make up the roster. High-quality Mugen creators have done an impressive job
M.U.G.E.N - Street Fighter Zero 3 MUGEN by H-Loader DOWNLOAD: https://zerx-mugen.blogspot.com/2016/07/street-fighter-zero-3-mugen. Facebook·M.U.G.E.N - Up "Watch Mode" for CPU battles
If you want, I can produce: (a) a full web article based on the suggested structure, (b) step-by-step M.U.G.E.N configuration files and example folder layout (using only original or permissively licensed assets), or (c) a short legal-compliance checklist for hosting fan content. Which would you like?